Basic CSS: Use an id Attribute to style an element. Can someone help me figure out my mistake

<link href="https://fonts.googleapis.com/css?family=Lobster" rel="stylesheet" type="text/css">
<style>
  .red-text {
    color: red;
  }

  h2 {
    font-family: Lobster, monospace;
  }

  p {
    font-size: 16px;
    font-family: monospace;
  }

  .thick-green-border {
    border-color: green;
    border-width: 10px;
    border-style: solid;
    border-radius: 50%;
  }

  .smaller-image {
    width: 100px;
  }

  .silver-background {
    background-color: silver;
  }

  #cat-photo-element {
    background-color: green;
  }
</style>

<h2 class="red-text">CatPhotoApp</h2>
<main>
  <p class="red-text">Click here to view more <a href="#">cat photos</a>.</p>
  
  <a href="#"><img class="smaller-image thick-green-border" src='//discourse-cloud-file-uploads.s3.dualstack.us-west-2.amazonaws.com/freecodecamp/original/3X/6/1/61a3499c5abb165be990aa0c1abd23342e60c663.jpg' alt="A cute orange cat lying on its back."></a>
  
  <div class="silver-background">
    <p>Things cats love:</p>
    <ul>
      <li>cat nip</li>
      <li>laser pointers</li>
      <li>lasagna</li>
    </ul>
    <p>Top 3 things cats hate:</p>
    <ol>
      <li>flea treatment</li>
      <li>thunder</li>
      <li>other cats</li>
    </ol>
  </div>
  
  <form action="/submit-cat-photo" id="cat-photo-form">
    <label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
    <label><input type="radio" name="indoor-outdoor"> Outdoor</label><br>
    <label><input type="checkbox" name="personality" checked> Loving</label>
    <label><input type="checkbox" name="personality"> Lazy</label>
    <label><input type="checkbox" name="personality"> Energetic</label><br>
    <input type="text" placeholder="cat photo URL" required>
    <button type="submit">Submit</button>
  </form>
</main>

Please post a link to the challenge. I don’t know what the html is.

heres the link

https://learn.freecodecamp.org/responsive-web-design/basic-css/use-an-id-attribute-to-style-an-element

Thanks. What about your html code?

You need to wrap it the code in ``` on both sides. Otherwise, I won’t be able to see the code.

Well, I’m going to take a blind guess while I wait for your html code.

My guess is that

#cat-photo-element {
background-color: green;
}

Is not the correct id name for the form tag. Double check that.